If your baby is diagnosed with myelomeningocele, or certain other types of spina bifida, there is a risk for a condition called hydrocephalus. Babies with hydrocephalus have excess fluid around their brains.

If your baby has too much of this fluid, called cerebrospinal fluid, it can put excess pressure on the brain. If not treated, hydrocephalus can be life threatening or cause physical or cognitive problems for your child.

Hydrocephalus occurs with myelomeningocele because an opening in the spinal cord results in loss of the fluid surrounding the nervous system. This causes brain to extend into the spinal canal, which is called an Arnold Chiari II malformation. This malformation blocks the drainage of cerebrospinal fluid, causing the build-up of excess fluid present in hydrocephalus.

The good news is that fetal surgery for repair of myelomeningocele helps reduce or even eliminate hydrocephalus and the Chiari malformation. Successful surgery means children may not need surgery or require fewer surgeries after birth to place drains, called shunts, to drain cerebrospinal fluid.

A landmark, seven-year trial, called Management of Myelomeningocele Study, showed clear benefit for babies who had fetal surgery to treat spina bifida. The study found fetal surgery reduced the need for a shunt by almost 30 percent and significantly improved the child's chances of being able to walk.

There was no increased risk of death for the baby or the mother when the fetal surgery group was compared with a group that received surgery after birth.